JPH05220680A - Electrostatic actuator - Google Patents

Abstract

PURPOSE:To provide a large displacement quantity in a micro-electrostatic actuator. CONSTITUTION:A fixed member 1, a movable member 4 which has a plurality of teeth 7 and is connected to the fixed member 1 by a pair of support members 2A, 2B, and first and second driving members 31A, 31B, 32A, 32B having leaf springs 8 to displace the movable member 4 are arranged on a glass base plate 5, and the movable member 1 is displaced in one direction by utilizing the electrostatic force between these driving members and the movable member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microminiature electrostatic actuator having an outer dimension of millimeter or less, which displaces an object by utilizing electrostatic force between electrodes.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional example of this type. This is because the fixed electrode K and the movable electrode M, which are comb-shaped, are meshed with each other with a proper gap, and a voltage is applied to both to displace the comb-shaped fixed electrode K in the longitudinal direction of the comb teeth, which is proportional to the number of comb teeth. An electrostatic drive force is obtained. When a voltage is applied as described above, it is displaced in the direction of arrow R1, and when a voltage is applied as described above, it is displaced in the direction of arrow R2. In addition, H
Indicates a support portion (fixed portion). The electrostatic driving force F acting in this case is ε is the relative permittivity, ε _{0 is} the permittivity of vacuum, d is the gap distance, n is the number of comb teeth, t is the tooth thickness, and V is the applied voltage. F = ε · ε ₀ · n · t · V ² / 2d (1) FIG. 14 shows another conventional example. In this method, the fixed electrode K and the movable electrode M are arranged so as to face each other, and a voltage is applied to both of them to obtain an electrostatic driving force in the direction of reducing the gap as indicated by the arrow. Electrostatic driving force F in this case
Let ε be the relative permittivity, ε _{0 be} the vacuum permittivity, d be the gap distance, S be the facing area, and V be the applied voltage. F = ε · ε ₀ · S · V ² / 2d ² ( 2) is expressed as

[0003]

However, since the displacement amount of any of the above is extremely small, its application range and application are limited, and there is a problem that it cannot be applied to the application requiring a large displacement amount. Therefore, an object of the present invention is to make it possible to generate a particularly large displacement amount.

[0004]

In order to solve such a problem, in the first invention, a fixed member and a movable member which has a plurality of teeth and is coupled to the fixed member via a pair of supporting members. And a pair of first and second driving members that have a leaf spring that engages with the movable member and that displaces the leaf spring, are arranged on the substrate, and the first and second driving members and the movable member are It is characterized in that the movable member is displaced in one direction by utilizing the electrostatic force between them. In the second invention, a movable member, a pair of first drive members having a leaf spring for displacing the movable member in a first direction, and a pair of first driving members having a leaf spring for displacing the movable member in a second direction 1 A pair of second driving members are arranged on a fixed member, and the movable member can be displaced in both directions by utilizing electrostatic force between each of the driving members and the movable member. It is characterized in that it is held at a fixed position by utilizing the electrostatic force between them.

In the third invention, at least a pair of first driving members having a movable member, three fixed electrodes and a plate spring for displacing the movable member in the first direction, three fixed electrodes and a plate. A fixed electrode having a spring and at least one pair of second driving members for displacing the movable member in the second direction, the fixed electrode electrically connected to the leaf spring and the other two fixed electrodes; It is characterized in that the movable member can be displaced in both directions by utilizing the electrostatic force between them. According to a fourth aspect of the present invention, a disk-shaped rotating member and a plurality of drive members that have a leaf spring and are provided concentrically with respect to the rotating member are provided on a pair of fixed electrodes that are bonded together via an insulator. Arranging, rotationally displacing the rotating member by using electrostatic force between all of the driving members and the upper fixed electrode, and holding the rotating member by using electrostatic force between the pair of fixed electrodes. Is characterized by.

[0006]

A large displacement can be obtained by utilizing the spring force of a leaf spring including a ratchet mechanism.

[0007]

1 is a perspective view showing an embodiment of the present invention. In the figure, 1 is a fixing member, 2A and 2B are supporting members such as leaf springs, 31A and 31B are first driving members, and 32
A and 32B are second drive members, 4 is a movable member, 5 is a glass substrate as a substrate, 6 is a guide member, 7 is a tooth formed on the movable member 4, 8 is a leaf spring, and SW1 and SW2 are switches. .. That is, the movable member 4 is coupled to the fixed member 1 via the support members 2A and 2B, and these are arranged on the glass substrate 5 as an insulating substrate. The movable member 4 is hollowed out at its central portion as shown in the drawing, and is engaged with the guide member 6 formed on the glass substrate 5 at this portion. Further, a large number of teeth 7 as shown in the drawing are formed on the movable member 4, and the first driving member 3
1A, 31B and the second drive members 32A, 32B are formed with leaf springs 8 that engage with them. Further, the first driving members 31A and 31B are connected to the power source E1 via the switch SW1, and the second driving members 32A and 32B are connected to the power source E2 via the switch SW2.

FIG. 2 is an explanatory diagram for explaining the operation of FIG. This shows a cross section taken along the line AA of FIG. 1, 31A is a first drive member, 32A is a second drive member, and 6A.
Is a guide member, 7 is a tooth, and 8 is a leaf spring. The driving members 31A and 32A are respectively connected to the power sources E1 and E2, and the other ends of the power sources E1 and E2 are grounded via the movable member 4 or directly. SW1 and SW2 are switches,
In FIG. 2 (a), both are in the off state, so
No action occurs in this state. Here, FIG.
When SW2 is turned on and the voltage E2 is applied between the second drive member 32A and the movable member 4 as in (B), the leaf spring 8 of the second drive member 32A engages with the teeth 7 of the movable member 4. At this time, the leaf springs 8 engage the corresponding teeth 7 by pushing the corners of the teeth 7. After that, as shown in Figure 2 (c), SW2
Is turned off, the movable member 4 is moved leftward in the figure by the restoring force of the leaf spring 8 of the second drive member 32A. SW
2 is turned off and then SW1 is turned on, this time, the leaf spring 8 of the first drive member 31A and the tooth 7 of the movable member 4 and FIG.
The contact is made as shown in FIG. 2C, and then the tooth 7 is engaged as shown in FIG. Thus, this embodiment can be said to utilize the so-called ratchet mechanism.

FIG. 3 is a perspective view showing a second embodiment of the present invention, FIG. 4 is an assembly configuration diagram thereof, and FIG. 5 is an explanatory view for explaining its operation. As shown in FIGS. 3 and 4, the fixed electrode 11A is formed on the fixed member 11, and a pair of forward drive members 33A and 33B, a pair of reverse drive members 34A and 34B, and a movable electrode are formed on the fixed electrode 11A. A member 41 is provided and configured. A pair of forward drive members 33A, 33
B and a pair of reverse drive members 34A and 34B are connected to a power source E1 via switches SW11 and SW12, respectively, and the switches SW11 and SW12 operate alternately so that when one is on, the other is off. And Note that 41A is an insulator.

The operation of the electrostatic actuator constructed as above will be described with reference to FIG. The same figure (a)
When the voltage E1 is applied between the drive member and the movable member 41 as described above, the leaf spring 8 of the drive member pushes the movable member 41 while being deflected by the electrostatic force F1 as shown by the dotted line in the figure, so the tip of the leaf spring 8 is a moves between the contact positions b and c of the movable member 41. This is a side view of the electrostatic actuator, but when viewed from above, it becomes as shown in the same figure (b), and in this case, it moves to the right direction (x) in the figure. After displacing the movable member 41 in this manner, the switches SW11 and SW12 shown in FIG. 3 are turned off and the switch SW2 is turned on, and the voltage E2 is applied between the fixed member 11 and the movable member 41 ((c)). Hold (stop) as shown in. When the voltage E1 and the voltage E2 are applied, as shown in (d), the voltage E1 is applied for a certain time to displace the movable member 41, and then the voltage E2 is applied for a certain time immediately before the movable member 41 is turned off. After the holding, the voltage E1 is applied again immediately before the voltage E2 is turned off, and the operation of driving the movable member 41 for a certain period of time is repeatedly performed to obtain a large displacement. It should be noted that here, the case where the moving direction of the movable member is the reverse direction shown in FIG. 3 has been described. Therefore, it can be said that this example is capable of bidirectional displacement.

FIG. 6 is a perspective view showing a third embodiment of the present invention, FIG. 7 is a sectional view showing the structure of a driving member, and FIG. 8 is an explanatory view for explaining the operation of FIG. As shown in FIG. 6, this includes a pair of forward drive members on the glass substrate 5.
The sets 35A, 35B, 36A, 36B, two sets of reverse drive members 37A, 37B, 38A, 38B, and the movable member 42 are arranged. As shown in FIG. 7, each driving member is composed of first to third fixed electrodes 11A to 11C, and the electrodes are insulated from each other via insulators 11E and 11F. Further, the leaf spring portion 1 is attached to the second fixed electrode 11B.
1D is formed. Further, the second fixed electrode 11B is connected to the negative side of the power source E, and the first fixed electrode 11A and the third fixed electrode 11C are switches SW1 and SW2, respectively.
Is connected to the positive electrode side of the power source E via.

The operation of the electrostatic actuator shown in FIG. 6 will be described with reference to FIG. That is, the same figure (a)
Indicates that both switches SW1 and SW1 are off, and no operation is performed in this case. Next, switch SW
1 is turned on to turn on the first fixed electrode 11A and the second fixed electrode 11
When a voltage is applied between B and B, the plate spring portion 11D of the second fixed electrode 11B is driven by the electrostatic force therebetween, whereby the movable member 42 is displaced to the left side in the drawing. Then, the switch SW1 is turned off as shown in FIG.
When W2 is turned on, the leaf spring portion 1 of the second fixed electrode 11B
1D is pulled up to the third fixed electrode 11C side. After that, if both the switches SW1 and SW1 are turned off as shown in FIG. 6D, the initial state is established and the movable member 42 is stopped at this position. After that, by repeating the same operation as described above, the movable member 42 can be sequentially moved to the left side in the drawing. In this example, the tip of the leaf spring portion 11D is driven as if drawing a circle on the paper surface of FIG. Although the case where the drive member on the right side is operated has been described above, the drive member on the left side can also be operated in the same manner as described above.
In this example as well, bidirectional displacement is possible.

By the way, the electrostatic actuator as described above is manufactured by utilizing the microfabrication technique of IC manufacturing. Here, a method of manufacturing the electrostatic actuator as shown in FIG. 6 will be briefly described. 9A to 9C show the process. First, as shown in FIG. 9A, an oxide film is deposited on the silicon substrate by sputtering, and then, as shown in FIG. 9B, from the lower side of the silicon substrate. Etching is performed to form each part. Then, in order to insulate each part, a nitride film is formed by, for example, a CVD method (vapor phase growth method) (see FIG.
And the etching process is performed from the lower surface as shown in FIG. Next, as shown in (e) of the figure, it is fixed to the glass substrate by an electrostatic bonding method or the like, and finally, as shown in (f) of the figure, the oxide film is removed by etching to complete.

FIG. 10 is a perspective view showing a fourth embodiment of the present invention, FIG. 11 is its assembly configuration diagram, and FIG. 12 is its sectional view. As is apparent from FIGS. 10 and 11, this corresponds to, for example, a modification of the second embodiment shown in FIG. 3 or FIG. 4, and the second embodiment performs a linear movement while the second embodiment performs a rotational movement. It can be said that it was done. That is,
The first and second fixed electrodes 12 and 13 are attached to each other via an insulator 14, and a plurality of driving members 39 on which the leaf springs 8 are formed are provided on the first fixed electrode 12 as a rotating body (a disk-shaped member). The movable member 15 is arranged in a circle according to the diameter thereof. In addition, 9 is a connecting wire for electrically connecting a plurality of driving members 39, 1
Reference numeral 4 is an insulator, E1 and E2 are power supplies, and SW1 and SW2 are switches. The operation is similar to that of the second embodiment,
A brief description will be given below. First, when the switch SW1 is turned on and the voltage E1 is applied between the plurality of driving members 39 and the first fixed electrode 12 via the connection line 9, each driving member 39
The pressing force by the leaf spring 8 provided on the rotary body 15 is applied to the rotary body 15, and the rotary body 15 rotates in the direction of arrow R.
When the rotating body 15 is stopped, the switch SW1 is turned off and the switch SW2 is turned on to apply the voltage E2 between the first and second fixed electrodes 12 and 13.

[0015]

According to the present invention, since the spring force of the leaf spring including the ratchet mechanism is utilized, there is an advantage that a large amount of displacement can be obtained with a relatively simple structure.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of FIG.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

4 is an assembly configuration diagram of FIG. 3. FIG.

5 is an explanatory diagram for explaining the operation of FIG. 3. FIG.

FIG. 6 is a perspective view showing a third embodiment of the present invention.

FIG. 7 is a side view showing the driving member of FIG.

8 is an explanatory diagram for explaining the operation of FIG. 6. FIG.

FIG. 9 is an explanatory diagram for explaining an example of the manufacturing method of FIG. 6.

FIG. 10 is a perspective view showing a fourth embodiment of the present invention.

FIG. 11 is an assembly configuration diagram of FIG. 10;

12 is a cross-sectional view of FIG.

FIG. 13 is a schematic diagram showing a conventional example.

FIG. 14 is a schematic diagram showing another conventional example.

[Explanation of symbols]

1, 11 ... Fixing member, 2A, 2B ... Supporting member, 31-3
9 ... Driving member, 4, 41, 42 ... Movable member, 5 ... Glass substrate, 6 ... Guide member, 7 ... Tooth, 8, 11D ... Leaf spring, 9
... Connecting wire, 11F, 11E, 14, 41A ... Insulator, 1
1A, 11B, 11C, 12, 13 ... Fixed electrode, 15 ...
Rotating body.

Claims (4)

[Claims] 1. A fixed member, a movable member having a plurality of teeth and coupled to the fixed member via a pair of support members, and a leaf spring engaging with the movable member, and displacing the leaf spring.
A pair of first and second driving members are arranged on the substrate, and the movable member is displaced in one direction by using electrostatic force between the first and second driving members and the movable member. Characteristic electrostatic actuator. 2. A pair of first driving members having a movable member and a plate spring for displacing the movable member in a first direction, and a pair of plates having a plate spring for displacing the movable member in a second direction. Second driving member is disposed on the fixed member, and the movable member is bidirectionally displaceable by utilizing the electrostatic force between each of the driving members and the movable member, and between the fixed member and the movable member. An electrostatic actuator characterized in that it is held at a fixed position by utilizing the electrostatic force of. 3. A movable member, at least one pair of first driving members having three fixed electrodes and leaf springs for displacing the movable member in a first direction, and three fixed electrodes and leaf springs. At least one pair of second driving members for displacing the movable member in the second direction are arranged on a substrate, and an electrostatic force between a fixed electrode electrically connected to the leaf spring and two other fixed electrodes. An electrostatic actuator characterized in that a movable member is bidirectionally displaceable by utilizing. 4. A disk-shaped rotary member and a plurality of drive members, each having a leaf spring and being concentric with the rotary member, are arranged on a pair of fixed electrodes bonded together via an insulator. Then, the rotating member is rotationally displaced by using the electrostatic force between all of the driving members and the upper fixed electrode, and the rotating member is held by using the electrostatic force between the pair of fixed electrodes. Characteristic electrostatic actuator.